There is fear and danger in the land and many are fleeing to sanctuaries, within and without. The appeal to fear and insecurity, to ignorance and bigotry, to religious zealotry and ethnic nationalism, to " make America great again", to ban Muslims, to deport millions, to " bring back the jobs", to tear up trade agreements, to repeal Obamacare, to build the Wall and make Mexico pay for it, calling the media  " the enemies of the people", questioning the integrity of the courts and the competence of the intelligence services, is roiling the land ( two Indian engineers going to a bar for an after-work drink are accosted and shot, one killed, after being told to go back to their country; many are taking to the streets to protests; some are seeking sanctuary and many are fleeing to Canada).
    Restricting trade and immigration is a toxic. It could damage the economy. Trade is necessary for every nation. It is a means of selling what it has and buying what it needs. There have to be rules and those are contained in the agreements negotiated, like NAFTA.
     Some countries run a deficit and that is not necessarily bad and may indeed be a good sign. When, as in the case of US and Mexico, there are many reasons. Firstly, the US has a very strong currency much more valuable than Mexico's. So it is cheaper for American consumers to buy much more of what they want ( avocados, tequila, cars, oil and gas etc.), while the Mexicans cannot afford to buy as much from the US. US/Mexico trade is worth $581 billion+ with a $ 55 billion deficit; US/China has a $659 billion trade with $ 360 deficit and Us /Canada has a $575 billion trade with a $ 15billion deficit. In the case of China, much of what it sells to the US is made by American corporations in China and it is very inexpensive and so shoppers at Walmart and other outlets, get a bargain, buy a lot and the corporations hire workers and make a huge profit and consumers save. The same with Mexico and Canada. Millions of jobs are created on all sides (  the Us/Canada trade is responsible for 9 million jobs in 35 states in the US and 2 million in Canada.
     So if, as Trump threatens, he tears up the NAFTA agreement,  American consumers will have to pay more for products they need and many millions will lose their jobs. That is why many states are calling on Trump not to restrict trade with Canada. We share a long border and millions travel each year back and forth for shopping and holidays and visiting friends and relatives too.
     In the case of Mexico, Trump wants to build a wall, ostensibly to keep out illegal immigrants, many of whom come from various countries in Central and South America and elsewhere and cross the border into the US. He wants the Mexican to pay for the wall but that has been roundly rejected, so he is using the scrapping of NAFTA as a means of forcing the Mexicans to make a deal. That will not happen ( probably, if he had not been so loud and bullying, some deal could have been worked out quietly, but Trump screams insults ( rapists and criminals), rather than negotiate quietly. The $55 billion deficit is due to cheap Mexican goods and the high American dollar. American customers can easily buy Mexican but Mexicans cannot buy American.
     China has been the manufacturer to the world for over 20 years. It is a combination of cheap labour and a Chinese government that in the 90s came to realize that it has to open ( to get rich is good, as Deng Chao Ping noted ) up in order to feed its teeming population. Many corporations relocated to China and China flourished ( even Trump wanted to do business there....his clothing line but not hotels), as they produced all manner of goods that were eagerly sought after, from television to clothing to everything. Its trade deficit grew with the US as, not many Chinese consumers could afford to buy American. So Trump used China and the deficit to whip up anger against China, accusing it of, among other things of currency manipulation ( while he and his daughter continue to make products there ).
     If Trump goes ahead and try to impose tariffs or any other punitive measures on Canada, Mexico or China, it will be Americans, people and corporations that will suffer, whether it be, by paying more for goods or losing their jobs. He makes policy on the fly, without much thought or information. It may have worked in the election campaign but not as government policies. Ignorance, threats, bullying of trading partners have serious consequences and so the wall, if built will be paid for by American taxpayers; the trade agreements, if they are scrapped will cost American jobs and if tariffs are placed on goods coming into the country, it will be the American consumers who will pay.
     Immigration and the 11 million " undocumented" won a lot of support for Trump and won him the White House, but now the reality check. His first attempt to ban immigration from Libya, Yemen, Sudan, Iraq, Iran, Somalia and Syria, by Executive Order was a disaster. It created a nightmare for travellers and not just from these countries and was quickly and successfully challenged in the courts ( District and Appeals , where all 4 judges ruled against the ban ( Trump tried to hide behind an Obama restriction, but failed ). Trump has gone back to the drawing board and a new Order is expected.
     In the meantime, there is fear in the land as people are rounded up and deported ( on the grounds that they are criminals, no matter how small the " crime" or how long they have been in the country. Many cities and churches have declared themselves to be " sanctuary" and refusing to go along with the ban or to cooperate with immigration officials. Many fear-stricken people are fleeing across icy fields to the Canadian border, seeking refuge in Canada. Trump's action has led to a petition signed by 1.8 million in Britain, to ban him from a proposed visit and forced a debate in Parliament, whose Speaker "is  strongly opposed" to Trump addressing the House of Commons and thus banned from doing so. The Europeans have also been very critical of the " Muslim ban".
     The 11 million " undocumented" perform many tasks, from babysitting to gardening to picking crops to construction, to restaurants to working in factories and slaughter houses ( jobs that are "dirty", backbreaking and dangerous and which " Americans" do not want to do. They are a very important part of the work force and already farmers and builders and restaurants etc. are complaining ( even the Trump vineyard has approached the  authorities to get " foreign workers" to come in). These are necessary work and the workers pay billions in taxes but do not collect Social Security ( even though they have contributed billions ). Another campaign promise that is having serious consequences.
          

     The Rule of Law and an Independent Judiciary ( together with the Right to Vote ) are the pillars of Democracy. The undermining of any or all is a dangerous threat to Democracy and that is what Trump has done, with his immigration ban and calling the judge who granted a stay, a " so called judge" ( this coming on top of his racist comments on another judge. who was presiding over the Trump University fraud case, calling him a " Mexican" ( he is Mexican-American, born in the US).
     The Rule of Law, establishes that " all are equal before the law; the law apply equally to all and that no one is above the law ". The immigration ban on all coming from 7 majority Muslim countries ( but giving preference to Christians ), even those with visas and green cards ( work permits) and those with special visas ( those who worked for and with Americans, as advisers, translators etc. and whose lives may be in danger for this), is a clear breach of " due process " ( the right to be treated equally and the right to be presumed innocent) and clearly establishes a religious bias and discriminates). The argument that they pose a terrorist threat is not demonstrated by that fact that no one from any of these ( Libya, Yemen, Syria, Iraq, Iran, Somalia), countries has committed a terrorist in US ( excluded from the ban are Saudi Arabia, Egypt, Pakistan, Indonesia, the largest Muslim states, but close allies and trading partners , if not business of Trump and his inner circle ). There was an immediate at home and abroad. Lawyers and thousands of protesters went to American airports to protest and help those who had travelled to US, legally and who were being turned away, some having their visas taken way. Condemnation from France, Germany and the EU and in Britain the Speaker of the House of Commons, John Bercow said that he was  " strongly opposed "  to Trump speaking in the House ( Trump had been invited to Britain by PM Theresa May on her visit to US. Addressing the House is  an honour sometime granted to foreign leaders ) " Before the imposition of the migrant ban, I would myself been strongly opposed to an address by Pres. Trump...after the imposition of the migrant ban by Pres. Trump I am even more strongly opposed to an address by Pres. Trump in Westminster Hall", he said to applause in the House. He cited the Commons opposition to " racism and to sexism and our support for equality before the law and an independent judiciary".
     An independent judiciary, ensures that the law would be respected and that anyone who tries to undermine the law or who acts illegally or unconstitutionally, would be prevented from doing so. The independence of the judiciary is necessary to stop arbitrariness and dictatorial rule. This has not sit well with Trump, who during the campaign used racist remarks about Judge Curriel, calling him Mexican  and doubting his objectivity because his ancestry ( Trump ad called Mexicans rapists and criminals. The judge was born in the US ). Now he is attacking the federal judge who has ruled against the " ban", saying he is a " so-called" judge ( this is a judge who was appointed by Pres. GW Bush and confirmed 99-0 by the Senate. No Mexican here " real American. Judges interpret laws and apply them, after listening to the arguments from both sides. This is their function as the arbiter of the law and its application. The independence of the judiciary is threatened when the President act like a bully and when he disparages them. Thankfully, Federal judges are appointed for life and are thus insulated from such cowardly and vicious attacks. No one is above the law, not any individual and certainly ( especially ) not the President. American colonies fought for their independence from a " tyrannical monarch" and they cherish their " rights and freedoms "and the Founding Fathers establish the " checks and balances " to ensure that no tyrant exercise power against the people or the Constitution, which the President swear to " uphold and protect". If Trump or anyone else does not like the decision of a judge or a court, they can appeal it. Trump chose to attack first. This is his wont and he has done this time and again, against the media, the intelligence agencies, the military and now the Judiciary.
     He weakens the basis of his power, of the democracy he has sworn to protect and the Rule of Law. This has all the hall marks of a constitutional crisis.